College of Marine Science and Engineering, Nanjing Normal University, Jiangsu Province Engineering Research Center for Aquatic Animals Breeding and Green Efficient Aquacultural Technology, Nanjing 210023, China.
College of Marine Science and Engineering, Nanjing Normal University, Jiangsu Province Engineering Research Center for Aquatic Animals Breeding and Green Efficient Aquacultural Technology, Nanjing 210023, China; Co-Innovation Center for Marine Bio-Industry Technology, Lian Yungang 222005, China.
Aquat Toxicol. 2023 Jul;260:106556. doi: 10.1016/j.aquatox.2023.106556. Epub 2023 May 9.
Hypoxia causes irreversible damage to aquatic animals. However, few reports have explored the effect of hypoxia stress and reoxygenation on intestinal homeostatic imbalance and consequent hepatopancreas-intestine axis health in crustacean. Herein, 180 Chinese mitten crabs (Eriocheir sinensis) were equally divided into control (DO 7.0 ± 0.2 mg/L) and treatment groups. The treatment group was exposed with continuous hypoxic stress (DO 3.0 ± 0.1 mg/L) for 96 h and then reoxygenated (DO 6.9 ± 0.1 mg/L) for 96 h. The effects on intestines and hepatopancreas of Chinese mitten crab were investigated, and the role of gut microbiota in hypoxia induced damages was explored. Hypoxia impaired intestinal tissue structure, and decreased swelling and the number of goblet cells, which are features that did not significantly improve after reoxygenation. With prolonged hypoxic stress, the activities of antioxidant enzymes (LDH, SOD and CAT) and MDA content in intestine were significantly elevated. Moreover, the level of oxidative stress increased, which led to upregulated apoptosis rate and expression of apoptosis-related genes (Caspase 3, Caspase 8 and BAX). In addition, the expression of immune related genes (MyD88, ALF1, Relish and Crustin) in hepatopancreas and intestine was both significantly induced under hypoxia, which activated the immune defense mechanism of Chinese mitten crab to adapt to the hypoxic environment. Furthermore, diversity and relative abundance of gut microbiota decreased noticeably during hypoxic stress; the number of beneficial bacteria downregulated. Finally, KEGG pathway analysis revealed that nine pathways were significantly enriched in intestinal microorganisms, including autoimmune disease and environmental adaptation. Collectively, these results suggested that hypoxia negatively affected E. sinensis health by triggering oxidative stress, altering the composition of the gut microbiota and inhibiting the immune response.
缺氧会对水生动物造成不可逆转的伤害。然而，目前很少有研究报道探讨缺氧应激和再氧合对甲壳类动物肠道内稳态失衡以及随之而来的肝胰腺-肠轴健康的影响。在此，将 180 只中华绒螯蟹（Eriocheir sinensis）平均分为对照组（DO 7.0±0.2 mg/L）和处理组。处理组持续暴露于低氧胁迫（DO 3.0±0.1 mg/L）96 h，然后再复氧（DO 6.9±0.1 mg/L）96 h。研究了低氧胁迫对中华绒螯蟹肠道和肝胰腺的影响，并探讨了肠道微生物群在缺氧诱导损伤中的作用。缺氧损伤了肠道组织的结构，减少了肠绒毛的肿胀和杯状细胞的数量，这些特征在再氧合后并没有显著改善。随着低氧胁迫时间的延长，肠组织中抗氧化酶（LDH、SOD 和 CAT）的活性和 MDA 含量显著升高。此外，氧化应激水平升高，导致细胞凋亡率和凋亡相关基因（Caspase 3、Caspase 8 和 BAX）的表达上调。此外，在缺氧条件下，肝胰腺和肠道中免疫相关基因（MyD88、ALF1、Relish 和 Crustin）的表达均显著上调，这激活了中华绒螯蟹的免疫防御机制以适应低氧环境。此外，低氧胁迫下肠道微生物多样性和相对丰度显著降低，有益菌数量下调。最后，KEGG 通路分析显示，肠道微生物中有 9 条通路显著富集，包括自身免疫性疾病和环境适应。综上所述，这些结果表明，缺氧通过引发氧化应激、改变肠道微生物群的组成以及抑制免疫反应，对中华绒螯蟹的健康产生负面影响。
